Toilets for removing waste products are well known. Typically, toilets incorporate three systems that work together to perform the flushing action: the bowl siphon, the flush mechanism and the refill mechanism. Working in concert, these three systems allow the flushing function of the toilet. Usually, the tank, positioned over the back of the bowl, contains water that is used to initiate the siphoning from the bowl to the sewage line, after which fresh water refills the bowl. When a user desires to flush the toilet, the user depresses the flush lever on the outside of the tank, which is connected on the inside of the tank to a movable chain or lever. Upon depression, the flush lever moves a chain or lever on the inside of the tank, thereby lifting and opening the flush valve and to cause water to flow from the tank and into the bowl initiate the toilet flush.
In many toilet designs, water flows directly into the bowl and disperses into the rim of the toilet bowl. The water releases into the bowl rather quickly, with flow form the tank into the bowl typically lasting approximately 2 to 4 seconds. The water flows from the rim, down a channel within the sides of the bowl and into the large hole at the bottom of the toilet (commonly known as a siphon jet). The siphon jet releases most of the water into an adjoining siphon tube, thereby initiating the siphon action. The siphoning action draws all of the water and waste out of the bowl and into the siphon tube. The waste and water continues through the other end of the siphon tube through an area known as the trapway and is then released into the wastewater line connected at the base of the toilet. Once the tank is emptied of its contents during the flush, the flush valve closes, and a floating mechanism which has now dropped in the tank to some residual amount initiates the opening of the filler valve. The filler valve provides fresh water to both the tank and the bowl through separate flows. Eventually the tank fills with water to a high enough level to cause the float to rise, thus shutting off the filler valve. At this point, the flushing cycle is complete.
The excessive consumption of potable water, however, remains a dilemma for water agencies, commercial building owners, homeowners, residents and sanitaryware manufacturers. An increasing global population has negatively affected the amount and quality of suitable water. In response to this global dilemma, many local and federal authorities have enacted regulations that reduce the water demand required by toilet flushing operations. In the United States, for instance, government agencies that regulate water usage have gradually reduced the threshold for fresh water use in toilets, from 7 gallons/flush (prior to the 1950s) to 5.5 gallons/flush (by the end of the 1960s) to 3.5 gallons/flush (in the 1980s). The National Energy Policy Act of 1995 now mandates that toilets sold in the United States can only use 1.6 gallons/flush (6 liters/flush). Current agency requirements further mandate that the activation means (usually the flush lever or button) for the flush valve assembly sustain a minimum “hold down” time of 1 second without exceeding 1.6 gallons/flush (6 liters/flush). It has been found, however, that the hydraulic performance characteristics of the flush valve are significantly enhanced if water evacuates the tank in a dumping time of less than 1 second, preferably 0.5 to 0.6 seconds.
Sanitaryware and flush valve manufacturers have attempted various techniques to comply with reduced water requirements and minimum “hold down” times. Such compliance has proven difficult to combine with enhanced flushing and sanitary performance. In the crowded art of producing a more reliable, more efficient and more powerful 1.6 gallon (6 liter) gravity toilet, one method to more effectively remove waste from the toilet bowl is to increase the hydraulic energy available during the flushing operation. Unfortunately, conventional flush valve configurations employ a coaxial flush valve assembly wherein the effective flow diameter through the flush valve opening is less than the orifice diameter of the flush valve inlet under dynamic conditions. Such configurations therefore do not utilize the maximum available hydraulic energy.
The inventor has overcome such detriments in toilet technology in co-pending application U.S. Ser. No. 10/232,878, filed Aug. 30, 2002 and entitled HIGH PERFORMANCE FLUSH VALVE ASSEMBLY (the entire disclosure of which is hereby incorporated by reference). This application discloses a flush valve assembly for a water tank of a toilet that includes a valve body secured thereto. The valve body has a base sleeve portion including a radiused inlet to increase the discharge coefficient of the valve opening. A flush cover member is coaxially and slidably mounted with respect to the valve body so that the valve opening is created therebetween when the flush cover member is removed form the valve body via reciprocating motion. The flush cover member is slidably movable between a first position, wherein the flush cover member is seated on the base sleeve portion of the valve body and thereby obstructs water flow through the valve opening, and a second position, wherein the second valve member is removed from the base sleeve portion of the valve body to permit water flow through the valve opening. A sealing member is provided to ensure a proper seal when the flush cover member is in the first position, and a guiding means is provided that properly aligns and guides the flush valve cover relative to the valve body. The flush valve assembly also includes a trip release mechanism that releases the effects of the flush lever on the flush cover member when the flush cover member reaches its second position, thereby returning the flush cover member to its first rest position prior to the flush lever returning to its own corresponding rest position. In this configuration, the disclosed flush valve assembly ensures compliance with the mandated water requirements and simultaneously provides enhanced cleanliness and waste removal capabilities. The flush valve assembly achieves these functions and also releases the effect of the flush lever so that the valve opening can close before the expiration of the mandated minimum “hold down” time (1 second without exceeding the total water per flush mandate of 1.6 gallons (6 liters)).
It is desirable to provide the aforementioned benefits in a flush valve assembly having additional flushing features. In particular, it is desirable to provide a flush valve assembly with enhanced noise dampening qualities and minimal splash back of water in the toilet tank. Such features should be incorporated in the flush valve assembly without compromising the water conservation benefits and hold down time of the prior disclosed flush valve assembly.